1. Field of the Invention
The invention relates to a connection between an electrode belt belonging to a heart rate monitor and to be positioned on the chest and a circumferential band to be wound around the body and to the structure of the electrode belt, as far as the above connection is concerned. A heart rate monitor is a device used in sports and medicine, the device measuring the pulse of a human heart by means of an electrode belt on the chest or by means of a device based on pressure measurement at the wrist.
2. Brief Description of the Related Art
Heart rate monitors typically comprise an electrode belt, a circumferential band and a display unit at the wrist. At its ends, the electrode belt is fastened to the circumferential band that is wound around the body of the person to be measured. Inside the electrode belt, on the side to be positioned against the body, there are electrodes measuring the electrical pulses generated by heartbeat, which pulses are then sent by a sender of the electrode belt to a receiver for instance at the wrist, the receiver also containing a memory and a display unit. Moreover, heart rate monitors can have such a structure that the electrode belt on the chest also comprises functions, such as display and memory, which were included in the receiver at the wrist in the above solution. Naturally, a heart rate monitor like this needs no transmitter-receiver technique, because all functions are contained in the electrode belt to be positioned on the chest. Some heart rate monitors have a structure comprising measuring devices at the wrist only, which measure the heartbeat by means of pressure changes in arteries. The present invention relates to heart rate monitors, comprising an electrode belt to be kept on the chest, and the invention relates especially to a connection between the electrode belt and a circumferential band and to the structure of the electrode belt, as far as the connection is concerned.
In accordance with the prior art, the connection between the electrode belt and the circumferential band consists in that a lock button of the band is passed from the inside (the side against the body) of the electrode belt through a hole in a mounting socket of the electrode belt and placed in the mounting socket outside the electrode belt. With the lock button mounted in the socket, the plane surfaces of the socket keep the button in place so that the button is not capable of returning inside the electrode belt, in which case the connection between the electrode belt and the circumferential band would come loose.
However, a drawback is associated with the prior art technique: when the electrode belt and the circumferential band are placed against the body and when the circumferential band is tightened in such a way that the electrode belt stays on the chest, the connection point is subjected to a force caused by the bent electrode belt and the tightened circumferential band, which force tries to drive the lock button out of the mounting socket. When the electrode belt has been placed on the chest, a force to the left of the person in question has an anticlockwise effect and a force to the right of the person has a clockwise effect. The problem becomes critical as for children and slim adults having a narrow chest: the electrode belt must then be bent much and the force directed to the connection between the electrode belt and the circumferential band is stronger still than when people with a broad chest are concerned.